This study evaluated the possible involvement of 5-HT 2B receptors in long-lasting hypotension to 5-hydroxytryptamine (5-HT), which is predominantly mediated by 5-HT 7 receptors, in anaesthetised vagosympathectomized rats. Intravenous injections of 5-HT and 5-carboxamidotryptamine (5-CT) elicited a dose-dependent hypotension that was dose-dependently antagonised by (R)-1-{(3-hydroxyphenyl)sulfonyl}-2-{2-(4- methyl-1-piperidinyl) ethyl} pyrrolidine (SB-269970; a selective 5-HT 7 receptor antagonist), but not by saline. Interestingly, α-methyl-5-(2-thienylmethoxy)-1H-indole-3-ethanamine (BW723C86; a 5-HT 2B receptor agonist) produced vasopressor responses without affecting hypotension to 5-HT. These results suggest that hypotension to 5-HT and 5-CT is mainly mediated by 5-HT 7 receptors, whilst the role of 5-HT 2B receptors seems unlikely.

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European Journal of Pharmacology
Department of Pharmacology

Centurion, D., Glusa, E., Sánchez-López, A., Valdivia, L. F., Saxena, P. R., & Villalón, C. (2004). 5-HT 7, but not 5-HT 2B, receptors mediate hypotension in vagosympathectomized rats. European Journal of Pharmacology, 502(3), 239–242. doi:10.1016/j.ejphar.2004.08.050